• Title, Summary, Keyword: exopolysaccharide

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Exopolysaccharide Production and Mycelial Growth in an Air-Lift Bioreactor Using Fomitopsis pinicola

  • Choi, Du-Bok;Maeng, Jeung-Moo;Ding, Ji-Lu;Cha, Wol-Suk
    • Journal of Microbiology and Biotechnology
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    • v.17 no.8
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    • pp.1369-1378
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    • 2007
  • For effective exopolysaccharide production and mycelial growth by a liquid culture of Fomitopsis pinicola in an air-lift bioreactor, the culture temperature, pH, carbon source, nitrogen source, and mineral source were initially investigated in a flask. The optimal temperature and pH for mycelial growth and exopolysaccharide production were $25^{\circ}C$ and 6.0, respectively. Among the various carbon sources tested, glucose was found to be the most suitable carbon source. In particular, the maximum mycelial growth and exopolysaccharide production were achieved in 4% glucose. The best nitrogen sources were yeast extract and malt extract. The optimal concentrations of yeast extract and malt extract were 0.5 and 0.1%, respectively. $K_2HPO_4\;and\;MgSO_4{\cdot}7H_2O$ were found to be the best mineral sources for mycelial growth and exopolysaccharide production. In order to investigate the effect of aeration on mycelial growth and exopolysaccharide production in an air-lift bioreactor, various aerations were tested for 8 days. The maximum mycelial growth and exopolysaccharide production were 7.9 g/l and 2.6 g/l, respectively, at 1.5 vvm of aeration. In addition, a batch culture in an air-lift bioreactor was carried out for 11 days under the optimal conditions. The maximum mycelial growth was 10.4 g/l, which was approximately 1.7-fold higher than that of basal medium. The exopolysaccharide production was increased with increased culture time. The maximum concentration of exopolysaccharide was 4.4 g/l, which was about 3.3-fold higher than that of basal medium. These results indicate that exopolysaccharide production increased in parallel with the growth of mycelium, and also show that product formation is associated with mycelial growth. The developed model in an air-lift bioreactor showed good agreement with experimental data and simulated results on mycelial growth and exopolysaccharide production in the culture of F. pinicola.

Cloning, Sequencing and Characterization of Acyltransferase Gene Involved in Exopolysaccharide Biosynthesis of Zoogloea ramigera 115SLR

  • Lee Sam-Pin;Troyano Esperanza;Lee Jin-Ho;Kim Hyun-Soo;Sinskey Anthony John
    • Journal of Microbiology and Biotechnology
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    • v.16 no.7
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    • pp.1163-1168
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    • 2006
  • The recombinant plasmid pLEX2FP complements the mutation in Zoogloea ramigera 115MM1, and the complemented mutant produces an exopolysaccharide that shows higher affinity for the calcofluor dye than the exopolysaccharide from Z. ramigera 115SLR, resulting in higher fluorescence intensity under UV light. A compositional and structural analysis of the exopolysaccharide from Z. ramigera 115MM1 showed that the different fluorescent properties were due to a lower content of acetyl groups when compared with Z. ramigera 115SLR exopolysaccharide. These results were in agreement with a sequence analysis of the gene carried in the plasmid pLEX2FP, which appeared to encode an O-acyltransferase highly homologous to the 3-O-acyltransferase of Streptomyces mycarofaciens. The gene encoding the acyltransferase from Z. ramigera 115SLR was expressed as a GST-fusion protein with 70,000 daltons in E. coli.

Exopolysaccharide Production by Aureobasidium pullulans - Appearance of Melanin Pigment - (Aureobasidium pullulans 에 의한 Exopolysaccharide 생산 - 멜라닌 색소의 출현에 관한 연구 -)

  • 김재형;이기영;강성홍
    • KSBB Journal
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    • v.4 no.2
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    • pp.134-142
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    • 1989
  • In exopolysaccharide fermentation by Aureobasidium pulluans, the effects culture conditions (concentration of nitrogen, potassium phosphate, dissolved oxygen, and initial pH) on the production of exopolysaccharide and the appearance of melanin pigment were investigated. The results are as follows. (1) The specific growth rate and the specific production rate of exopolysaccharide were inhibited by substrate when the carbon source concentration higher than $50g\;/\;{\ell}$ and the cell growth increased with increases of nitrogen source but exopolysaccharide production decreased with the nitrogen concentration when it become greater than $1\;g\;/\;{\ell}$. (2) The maximum cell growth and the maximum exopolysaccharide production were obtained at initial pH values of 3.0 and 7.5 respectively. As the initial pH increased, the yeast-like cells increased and the increased of dissolved oxygen increased the cell growth and exopolysaccharide production. (3) As the concentration of dissolved oxygen is increased or the concentration of nitrogen source is decreased, the period of melanin pigment appearance becomes shorter and the melanin pigment never appeared when the initial pH was less than 3.0 or the potassium phosphate was not added.

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Characteristics of Organic Substances Produced from Cochlodiniumpolykrikoides (Dinophyceae) (Cochlodinium polykrikoides(Dinophyceae)에서 분비되는 유기물질의 특성)

  • Kang, Yang-Soon;Kwon, Jung-No;An, Kyoung-Ho
    • ALGAE
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    • v.21 no.2
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    • pp.253-259
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    • 2006
  • Organic substances are released from phytoplankton cells during all phases of growth. The type and amounts of organic substance excreted and the effects of nutrient limitation are often highly species-specific. Dinoflagellate, Cochlodinium polykrikoides grown in batch culture produced an exopolysaccharide. Exopolysaccharide and intracellular polysaccharide concentrations increased as C. polykrikoides cultures progressed from exponential phase, through stationary phase, to declining phase. In the exponential phase, the concentration of exopolysaccharide was relatively low, but in the stationary phase, it showed a rapid increase which seemed to coincide with the depletion of nitrate from the medium. Of the 20 amino acids analyzed, proline dominated in the organic matter of all cultures ranging from 48.2 to 79.9 nmol L–1, and constituting the 20-90% of total amino acids, and followed by histamine varying from 0.7 to 47.5 nmol L–1. Leucine and cysteine were also abundant in the stationary phase. The release rates of exopolysaccharide and intracellualr polysaccharide were higher the end of stationary phase than in the exponential phase. Exopolysaccharide concentration per cell was more than two times higher during the end of stationary phase than that in exponential phase. C. polykrikoides produced extracellular polysaccharide at a rate of 47.04 pg cell–1 day–1.

Isolation Of Latobacillus Producing Exopolysaccharide and Optimization of its Production (Exopolysaccharide생산 유산균주의 분리 및 배양조건)

  • 배인휴;허정원
    • KSBB Journal
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    • v.17 no.2
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    • pp.169-175
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    • 2002
  • A lactic acid bacterial isolate Lactobacillus ssp. SCU-M which produces exopolysaccharide was identified and its cultural Condition was investigated. The optimum Conditions for exopolysaccharide(EPS) Production Of Lactobacillus ssp. SCU-M were 37$\^{C}$, pH 6.5, using medium composed of 1.5% galactose, 1.0% yeast extract, 0.25% peptone, 0.15% MgSO$_4$, 0.15% K$_2$HPO$_4$ and 0.1% tween 80 in distilled water. The EPS concentration after 48 hours at the Initial pH 6.5, 37$\^{C}$ in a flask culture was 1,680 mg/ℓ.

Isolation of Exopolysaccharide-Producing Bacillus polymyxa KS-1 and Some Properties of Exopolysaccharide (다당류를 생산하는 Bacillus polymyxa KS-1의 분리 및 생산 다당류의 특성)

  • 권기석;주현규;오태광
    • Microbiology and Biotechnology Letters
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    • v.20 no.1
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    • pp.34-39
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    • 1992
  • For the screening of new-functional and specific exopolysaccharide, a bacterium strain was isolated from soil through the two steps of screening. The isolated bacterium was identified as Bacillus polymyxa KS-1 according to the criteria of morphological, physiological, and chemical taxonomic analyses. The exopolysaccharide was composed of glucose:galactose: mannose and galactosamine in an approximate molar ratio of 1.00:0.36:1.02:1.10. The produced exopolysaccharide by Bacillus polymyxa KS-1 was found to be revealed new acidic polysaccharide which did not contain pentose, ketose, starch, and uronic acid.

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Axenic Culture of Gyrodinium impudicum Strain KG03, a Marine Red-tide Microalga that Produces Exopolysaccharide

  • Yim Joung Han;Lee Hong Kum
    • Journal of Microbiology
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    • v.42 no.4
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    • pp.305-314
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    • 2004
  • An exopolysaccharide-producing microalgal dinoflagellate was isolated from a red-tide bloom and des­ignated strain KG03. A bacteria-free culture of strain KG03 was achieved using a modified wash with phototaxis and antibiotic treatment. Combined treatment with neomycin and cephalosporin was the most effective for eliminating the bacteria associated with the microalgae. Strain KG03 was identified as Gyrodinium impudicum by analyzing the ITS regions of the 5.8S rDNA, 18S rDNA, morphological phenotype and fatty acid composition. The exopolysaccharide production and cell growth in a 300-ml photobioreactor were increased 2.7- and 2.4-fold, respectively, compared with that in a flask culture at the first isolation step.

A Kinetic Study for Exopolysaccharide Production in Submerged Mycelial Culture of an Entomopathogenic Fungus Paecilomyces tenuipes C240 (동충하초 Paecilomyces tenuipes C240의 균사체 배양에 의한 세포외 다당체 생산의 동력학적 연구)

  • Xu Chung Ping;Yun Jong Won
    • Journal of Life Science
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    • v.15 no.1
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    • pp.15-20
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    • 2005
  • The unstructured model was tested to describe mycelial growth, exopolysaccharide formation, and substrate consumption in submerged mycelial culture of Paeeiliomyees tenuipes C240. The Logistic equation for mycelial growth, the Luedeking-Piret equation for exopolysaccharide formation, and Luedeking­Piret-like equations for glucose consumptions were successfully incorporated into the model. The value of the key kinetic constants were: maximum specific growth rate ${\mu}m,\;0.7281\;h^{-1};$ growth­associated constant for exopolysaccharide production $(\alpha),\;0.1743g(g\;cells)^{-1}$; non-growth associated constant for exopolysaccharide production $(\beta),\;0.0019g(g\;cells)^{-1}\;;$ maintenance coefficient $(m_s),\;0.0572g\;(g\;cells)^{-1}$. When compared with batch experimental data, the model successfully provided a reasonable description for each parameter during the entire growth phase. The model showed that the production of exopolysaccharide in P. tenuipes C240 was growth-associated. The model tested in the present study can be applied to the design, scale-up, and control of fermentation process for other kinds of basidiomycetes or ascomycetes.

Effects of Carbon Substrates on Exopolysaccharide Production by Enterobacter sp. (Enterobacter sp. 의 다당 생산에 미치는 탄소원 기질의 영향)

  • Lee Ju-Ha;Lee Shin-Young
    • KSBB Journal
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    • v.20 no.1
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    • pp.26-33
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    • 2005
  • The effects of carbon sources for exopolysaccharide production during batch cultivation of an Enterobacter sp. isolated from the composter were investigated. The highest amount of exopolysaccharide was obtained when lactose was used as carbon source. Lactose in medium was converted into glucose and galactose. Glucose was metabolized fast and was completely consumed, but about $20\%$ of lactose was accumulated as galactose. On the other hand, enzyme activity was about $350\~450$ unit with the increase of lactose concentration. Thus, it was considered that the exopolysaccharide might be produced in the course of that lactose was hydrolyzed into glucose and galactose by $\beta-galactosidase$ with respect to that enzyme activity on lactose hydrolysis was accorded to the exopolysaccharide production. When glucose and galactose were added to lactose medium, respectively, it could be considered that glucose was as a repressor and galactose was as a inducer for $\beta-galactosidase$ synthesis even though the mechanisms were not elucidated. The increase of lactose concentration was almost ineffective to the specific growth rate $(0.133\~0.151\;hr^[-1})$ but showed the difference in the biomass content. The higher carbon source concentration, the more residual sugar remained. It was assumed that the optimum lactose concentration for exopolysaccharide production was $30\~70g/L.$ On the other hand, it was considered that the nitrogen acted as growth limiting nutrients to the cell growth. In the cases of 30 and 70 g/L of the fixed carbon concentrations, the increase of the nitrogen sources concentration caused a remarkable increase within the range of $0.059\~0.225\;hr^{-1}$ and $0.141\~0.237hr^{-1}$ of the specific growth rate, respectively, while there was no significant difference in biomass.

Cultural Conditions of Exopolysaccharide KS-1 Produced by Bacillus polymyxa KS-1 (Bacillus polymyxa KS-1에 의한 다당류 KS-1 생산의 발효 조건)

  • 권기석;윤병대주현규
    • KSBB Journal
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    • v.10 no.4
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    • pp.441-448
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    • 1995
  • Optimized fermentation medium and cultural conditions for the production or exopolysaccharide KS-1 with Bacillus polymyxa KS-1 was following as; 30g g1ucose, 2.59g yeast extract, $2.5g KH_2PO_4, 0.5g NaCl, 0.3g MgSO_4.7H_20, 0.1g CaC0_3 0.05g, FeSO_4.7H_2O, and 0.05g MnS0_4 . 4H_20in 1 liter distilled water. The exopolysaccharide production was influenced by the by the temperature and pH, the optimal conditions for the production of exopolysaccharide KS-1 seemed to be $30^{\circ}C$ and pH 7.0, respectively. About $10.3g/\ell$ of maximum exopolysaccharide was obtained al the initial pH 7.0, $30^{\circ}C$, 2vvm of aeration rate and 400 rpm of impeller speed in a jar fermentor.

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